Avidemux Forum

I'm using Avidemux 2.8—I think it's the latest version, although I haven't found the right section.
My complaint is that, for many years now, numerous filters have disappeared. I'm referring in particular to "reverse" and "add logo" for only a portion of a video, but I think there are many others.
It's time to bring these filters back. Sure, you can do everything with FFmpeg, but a graphical interface is easier than the complicated syntax.

I wanted to add some additional findings to this issue after quite a bit of testing.

I've been able to reproduce the same problem consistently on Debian 13. Pressing the Up Arrow during active video playback causes an odd stutter/jump, and playback doesn't advance properly. Seeking with the Up Arrow while playback is paused works normally.

Here's what I've tested on the same machine with the same video files:

- Official Avidemux 2.8.1 Linux AppImage — works perfectly.
- Official October 9, 2026 nightly AppImage — problem reproduced.
- Custom-compiled newer Avidemux using Qt6 — problem reproduced.
- Custom-compiled newer Avidemux using Qt5 — problem reproduced.
- Independently compiled newer Avidemux build — same problem.
- Newly compiled Avidemux 2.8.1 using the original 2.8.1 release source, Qt5, and FFmpeg 4.4.2 — works perfectly!

The newly compiled 2.8.1 includes some unrelated subtitle-preservation modifications, but the original playback and navigation code was left completely unchanged.

I also tested different video renderers, Dummy audio, and single Up Arrow taps to rule out keyboard auto-repeat. None resolved the problem in the newer builds.

Interestingly, the debug logs from the newer builds sometimes show a forward seek selecting the correct next keyframe, followed by playback resuming at an earlier position.

Based on these results, I strongly suspect a regression somewhere between the original 2.8.1 release and the newer 2.8.2 development code, or a change in one of its underlying dependencies.

I realize that doesn't identify the exact commit responsible, but hopefully it helps narrow down the investigation. At least I now have a working 2.8.1 build that restores the original seeking behavior.

Is there a particular playback/navigation change introduced after 2.8.1 that might explain this?

Quote from: roadhazard on October 28, 2026, 01:11:00 AMI don't know if I'm allowed to post it here but if I can, I'll gladly share it with the world. To me, this makes Avidemux 1000x better.

If you're not posting links to alternatives to Avidemux (bad form), and there are no potential licensing issues with anything you post, it really should not be an issue.

I would be interested in seeing the steps you use to get AI making subs.

I use https://sourceforge.net/projects/subtitle-workshop-classic/ which offers a lot of options but is complex to get use to it.  You can move timeings by just seeing the audio waveform which is often good for spotting start of dialog.  You also get warnings when the number of words exceed maximum average reading speed. It's easier to let some long sub lines extend into silence and it's easy to spot when the scene changes.  However, of course this is a lot of work to make a high quality subtitle or fix an existing one. I've noticed that a lot of .ass files fail to load because they are missing a leading 0. in the timing on each line.  Maybe the new version is better. Such .ass files can be fairly easily fixed with a text editor search replace.

I don't understand why you want to edit media that has srt subs.  Are you just removing ads?  I can see why removing a brand promo at the start can require a timing change for every sub, but you can do that pretty easily at: https://subtitletools.com/subtitle-sync-shifter
I use that all the time to fix timings.

As we all know, Avidemux is the best tool ever for easy and laser sharp cutting of MKV files. It's dead simple to use and does an excellent job of cutting. For years and years and years, I've been looking for a program that was as good as Avidemux with cutting -BUT- was able to retain/re-index SRT embedded subtitles.

I tried lots of MKV editors and Clever FFmpeg-GUI was the closet to what I needed but it's GUI (for whatever reason) seems backwards to me, it made my head hurt using it. I eventually gave up on my quest and forgot all about this journey ... until yesterday.

I had my brother use Claude to generate some helper files that would let you save your project file after cutting a video and take that .py file, the original MKV and the saved/cut MKV and would do some AI magic and presto chango, spit out a finished MKV, WITH SUBS, that are perfectly in sync with all the cuts you did!

I don't know if I'm allowed to post it here but if I can, I'll gladly share it with the world. To me, this makes Avidemux 1000x better.

Loving AI for stuff like this! My brother, nor myself, are developers but I'm really good at writing prompts.

Quote from: JanMeki on October 27, 2026, 02:31:41 PMIt says Display: RGB on the status bar.

This means that VDPAU display is not available.

Quote from: JanMeki on October 27, 2026, 02:31:41 PMDon't know why the intel decoder is not detected

Probably due to mismatch between the build and the host environment or due to another reason – please redirect stdout and stderr of appImage to a file and attach it to your reply here or post it on some pastebin equivalent as far as that service doesn't require login.

./relative/path/to/appImage 2>&1 | tee path/to/admlog.txt
Please replace paths containing personally identifiable information in a consistent way with placeholders prior to uploading the log.

Quote from: JanMeki on October 27, 2026, 02:31:41 PMEdit: Seems like Xvideo is the only video display mode that doesn't stretch the video frame. Is that the best one to use in my situation?

Yes, sure.

Quote from: JanMeki on October 27, 2026, 02:31:41 PMShould I use hw acceleration with that one?

As long as a closed-loop hw accel (libva hw decoder + libva display or VDPAU decoder + VDPAU display) is not available, NVDEC will always be beneficial. Therefore yes, use NVDEC then.

Quote from: JanMeki on October 27, 2026, 02:31:41 PMOpenGL makes the avidemux ui unusable (garbled) so that's out of the question.

Could you please eventually do build Avidemux locally to have a clear picture of what works and what doesn't?

I've been using video display: vdpau under display in the settings and nvdec under hw accel because it's the only one available (vdpau and libva are grayed out). It says Display: RGB on the status bar. Don't know why the intel decoder is not detected (I can use it in smplayer). This is on Skylake / Maxwell so there is no VP9 decoder and only the iGPU does h265 Main decoding. Maybe it's better to have hw acceleration off instead if multithreading is beneficial for VP9, h265 adn AV1? What are the optimal settings for my situation?

I don't see any difference capping the refresh rate of the gui. I feel like the scaling thing is the problem because if I use zoom 2:1 it plays in slomo and for every 1 sec the video is late by another 3000 ms.

Edit: Seems like Xvideo is the only video display mode that doesn't stretch the video frame. Is that the best one to use in my situation? Should I use hw acceleration with that one? OpenGL makes the avidemux ui unusable (garbled) so that's out of the question.

Quote from: JanMeki on October 25, 2026, 11:44:21 AM

Code Select Expand

/tmp/.mount_AvidemmePfkG/usr/bin/avidemux3_portable: symbol lookup error: /tmp/.mount_AvidemmePfkG/usr/lib/libgobject-2.0.so.0: undefined symbol: g_sort_array
/home/abc

My best bet would be recommending you to build Avidemux from source locally on your system (which is very easy on Linux, see github.com/mean00/avidemux2) so that libraries included into the appImage don't clash with system libraries.

You don't need to package and install Avidemux to run it, it can be excuted via a wrapper script (all explained in the README).

If the Avidemux window can't fit into the available screen real estate, Qt may distort the frame used to draw the video at least with the unaccelerated "Qt" video display if I am not mistaken. Avidemux won't add scroll bars to video frame, selecting zoom level too high will at least try to push parts of the GUI out of sight. If your (presumably) laptop has a high-density display, you might also consider disabling automatic HighDPI scaling in Qt, e.g. by setting the env var QT_SCALE_FACTOR to 1:

QT_SCALE_FACTOR=1 ./relative/path/to/Avidemux-x86_64_20261018_legacy.AppImage

Make sure you use an accelerated video display in Avidemux, i.e. NOT "Qt" / "RGB", preferably VDPAU (but with the graphics wired to Intel this might not work), OpenGL / QtGl or XVideo, else all the scaling work is done on the CPU. The best options are to use VDPAU hw decoder with VDPAU display or LibVA decoder with LibVA display (whatever works). If NVDEC is used, it always downloads decoded pictures to the main memory that need to be re-uploaded to the graphics card for display. This may still be beneficial, but not as efficient as it can be.

Another huge cause of lag can be the status bar itself, especially at 60 fps. Try hiding it via the "View" menü or restrict refresh rate of the GUI in Avidemux Preferences to a lower value e.g. by enabling the cap and setting the redraw interval to 20 ms (1000/20 = 50 fps) or higher.